"Have a good day" is a polite way to wish someone well for the rest of the day. It is often used as a friendly goodbye in conversations, emails, or customer service.
I hope the fans have enjoyed listening as much as I've enjoyed doing the games. I don't ever go to the park where I don't have a good day. I don't like losing. But I don't think I ever go to the park where I have a bad day. I don't think once. Bob Uecker
We can't control what the ratings will be. It's like, if you're going to go skiing, do you hope you'll have a good day of skiing? Yes. Do you hope you won't break your leg? Yes. David Hyde Pierce
When I pick up the ball and it feels nice and light and small I know I'm going to have a good day. But if I picked it up and it's big and heavy, I know I'm liable to get into a little trouble. Bob Feller
Who applies for that job? Who says "I want to work in lost luggage"? You don't have a good day. That's like having a job emptying port-a-potties. You're just going to catch crap all day long. Bill Engvall